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FIELD. QUADRUPLEX TELEGRAPH.

N0.f253.,0127. Patented Jam. 31,1882.

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, QUADRUPLEX TELEGRAPH. Y No. 253,027. Patented Jad11.31,1882.

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UNITEDv STATES PATENT OFFICE.

STEPHEN D. FIELD, OF NEW'y YORK7 N. Y.

QUADRUPLl-:x TELEGRAPH.

vSTL-"ECIFICATION forming part of Letters Patent No. 253,027, dated January 31, 1882.

Application filed November 25, 1881.

graphs, of which the following` is a specifica tion.

My invention consists in'the combination,

with a main line and a duplex or quadruplex telegraphic apparatus, ot two receivingrelays included in the same main circuit, and in a novel organization of the local circuits, and ot' a single sounder or other receiving-instrument, whereby the said instrument is operated by thejoint action of the said relays.

My invention further consists in the combination, with the two relays, ot'an improved adjusting device whereby both the armature-levers may be simultaneously adjusted. Two keys or transmitters are placed at the sending-station, and these are connected with two main batteries of unequal electro-motive force, the connections of the keys being so arranged that when both are in a position of rest a current ows overthe mainline havinga strength just sufcient to maintain the armature-lever of one of the three relays at the receiving-station in contact with its front stop. By the depression of one or the other of the keys independently, or of both simultaneously, the normal current isinterrupted, or currents otl different strengths are transmited over the line in such a manner that the movement ot' each key is properly responded to by the respective Sounders or other receivin g-instrumen ts which are placed in local circuits at the receivingstation;

For the sake ot' simplicity of explanation I have shown my invention as applied to the transmission of two independent communications simultaneously in the same direction over a single conductor, constituting what is technically termed aduplex,7 or, more properly, a diplex77 telegraph; but it is to be understood that any of the well-known methods of equating or balancing maybe applied to my invention, or combined with it in a manner well understood, soas to enable four distinct communications-two in each directionto be transmitted over the said conductor simultaneously.

(No model.)

In the accompanying drawings, Figures 1, 2, 3, and 4 are diagrams illustrating myinvention and its operation under different condilions, showing its application to the transmission of two independent communications simultaneously in the same direction. Fig. 5 is a diagram showing amoditication in the arrangement of one of the relays.

In the drawings, the main telegraph-line consists of an insulated telegraph-conductor extending from station A to station B, as shown at L. These two stations are assumed to be situated ata suitable distance from each other. At station A two independent transmitters are placed in connection with the line, as shown in the figures, where they are respectively designated as K and K. These transmitters may consist of ordinary key-levers worked directly by the Jringer of the operator, as shown in the several figures, or they may be operated by a special electro-magnet, local battery, and independent finger-key in awellknown manner. The transmitters K and K are each provided with circuit-preserving contact-sprin gs or Y other equivalent devices of well-known construction, so that when either transmitteris actuated acurrent maybe transmitter is depressed or in the act of transmitting a signal.

The transmitting-batteries are shown at E and E. These are respectively placed in branch circuits, and so connected with the respective keys or transmitters K and K' that their currents may be thrown upon the line, either separately or conjointly, without at any time interrupting the circuit. lt will be more convenient in explaining the operation of the system to consider the batteries E and E as two sections of one and the same battery (which they in fact are) the section E being preferably so vconstructed and arranged that its total electro-motive force is about twice as loo great as that of section E. For convenience of illustration it may be assumed that the section E consists ot' twelve cells or elements. The number of cells required in practice will necessarily vary in each particular case, as it must be made proportionate to the length of the line through which the apparatus is designed to be operated or to the resistance to be overcome by the electric current; but it is essential to maintain in every case substantially the same relative proportion between the electro-motive force ot' the two sections of the battery.

Considering', in the first place, the operation ofthe transmitters K and K', when they are employed for simultaneously sending two independent sets of signals, as in quadruplex working, it will be observed that they may occupy four different positions or relations, as follows: irst, both transmitters up; second, transmitter K down and transmitter Kl up; third, transmitter K up and transmitter K down, and,fourth, both transmitters down.

The organization of the several branch conductors between the transmitters K and K',

the batteries E and E, and the line L is such that four different electrical conditions may be produced upon the line, depending respectively upon the positions of the keys, as hereinbefore stated. In the first position referred to (which is that shown in Fig. l ofthe drawings) both transmitters are up or in a position of rest, and a current from the battery E passes over the line LJ The circuit through the transmitting apparatus may be traced as follows: from the earth at G at station A, by the wire 1 and 2, to the negative pole ot' the battery-section Ef; thence from the positive pole ot the said battery, by the wire 3, to the lever k of the key or transmitter K; thence by the circuit-spring p, wire 4, lever l.: of translnitter K, resting-contact n upon said lever, circuit-springn', and line-wire L to station B. Thus when the transmitters arcin their normal position, as shown in Fig. 1, a positive current from six cells traverses the line from the battery E', which for convenience ofexplanation may be assumed to have an'electro-motive force ot' six volts. If transmitter K alonebe depressed, the connections ofthe branch circuitatthe sendingstation are changed and assume the relation shown in Fig. 2. The circuit may now be traced as follows: from the earth at G, by the wires l and 9, resting-contact o, circuit-spring p', wire 10, to the negative pole ot' the batterysection E, and from the positive pole of said battery-section, by wire 1l, to working-contact m ofthe transmitter K, and thence by the circuit-spring n and wire L to station B. Thus transmitter K, when depressed, sends to line a positive current from the battery-section E, having an electro-motive force of twelve volts. It' now the transmitter K be depressed, the transmitter K remaining at rest, the circuit will be as follows, (referring to Fig. 3:) from the earth at G, by the wire-s 1 and 9, to the restingcontacto; thence by circuit-springp and wire 4 to the lever k of the key K; thence by the restin g-contact n of said transmitter, circuit-sprin g a', and wire 5 to the line-wire L, and thence to station B. In this position of the keys no battery whatever is in circuit at the transmitting-station, a direct connection being established between the earth at G and the line at L, and consequently no current will traverse the line. In case both transmitters K and K are depressed simultaneously, the route ofthe current will be as follows, (see Fig. 4:) from the earth at Gr, by the wires 1 and 2, to the negative pole of the battery-section E', and from the positive pole of said section, by the wire 3, to the lever k of the transmitter K; thence by the circuit-spring p and wire 10 to the negative pole of the battery-section E, and from the positive pole ot' said battery-section, by the wire l1, to working-contact m, and thence by circuit-spring n and wire L to station B. In this case both battery-sections E and E are in circuit, and a positive current is transmitted to line, having an electro-motive force of eighteen volts. The effect of these dii'erent strengths of current upon the receiving apparatus at station B will be next considered. lt, R', and R2 represent the electromagnets, which actuate three independent relays, which electro-magnets are included in series in the main line.

The electro-magnet of relay l is provided with an armature mounted upon a pivoted lever in the usual manner, as shown at 1', an adjustable retractile spring, t, and adjustable stops a a. A sounder, register, orother equivalent receiving-instrument, S, is included with a battery, e, in a local circuit traversing the armature-lever fr and contact-stop a, as indicated by the dotted lilies in the tigures.

The two electro-magnets R and R2 are provided with armatures r and r2, mounted upon pivoted levers iu the usual manner, and provided with adjustable stops b b c c', adjust-able retractile springs or links t and t2, the tension of which is prei'erabl y controlled by the operator through a device hereinafter to be described. The sounder or other receiving-instrument, S,is provided withaderentialelectro-magnet having two separate coils, s and s., which are so arranged with reference to the battery and connecting-wires that `the effect of a current traversing one coil will be neutralized by that of an equal current traversing the other coil. This is effected by the following arrangement: One of these coils, s, is included in a circuit from the positive pole of the local battery e', the wire 13, contact-stop b, armature-lever i", wire 12, whence it returns to the negative pole ofthe battery. The remaining coil, s', is included in a circuit from the positive pole ot' the battery c', wire 14, armatureleveriz, contact-stop c', wires 16 and 18, whence it returns to the negative pole of the battery. The armature-lever r2 is normally attracted to the magnet R2 when both keys at the sending- IOC IIO

station are at rest, and rests against contactstop c', as hereinafter explained. Thus equal currents traversing the coils s s in opposite directions from the battery c neutralize the effects of each other upon the receiving-imstrument. In order to insure an equal division of the current from the local battery through the two opposing coils, the resistance of the branch circuits should be approximately equal. In most instances this will not require special adjustment, but when found necessary such adjustment may be readily effected by inserting an artificial resistance in one or the other of thelines, as required.

In practice I have found it to be a matter of considerable difficulty for the receivingoperator to maintain the adjustment of two independent retractile springs attached to two di'erent relays, especially' when the insulation of the lines is variable, with such accuracy as to preserve at all times a proper relation between them, and thus insure the proper working of the apparatus. In order to avoid this difficulty/I have devised the apparatus shown in the figures, in which I make use of an equalizing-bar, F. To the extremities of this equalizing-bar are attached two links or tension-rods of thin wire, t and t2, the opposite ends of which are respectively attachedto the armature-levers r' and r2. A single retractile spring, T,the tension of which maybe adjusted by milled head and spindle d in the usual manner, is attached to the equaliziug-bar F at an intermediatepointbetween the point of attachmentof the links t and t2. The particular point atwhich the spring T is attached to the equalizing-bar F determines what proportion ofthe total elastic force of the spring shall be exerted upon the armature-levers r and r2, respectively. For example, in the operation of the apparatus it is necessary that the mechanical resistance offered to the movement of the armature lever r should be about three times as great as that offered to the movement of the armature-lever r2, and hence the spring T should be attached to the equaliZing-bar F by placing it in a notch ofthe bar at a point distant about one-fourth of its length from the end to which the link t is attached.

The precise point for attaching the spring T to the equaliZing-bar F may be determined by experiment, or otherwise, foreach particular instrument by moving it along the notched bar, and when once fixed it will seldom,`if ever, need tobechanged. Thetensionofthesinglespring T will require adjustment by the operator with reference to the varying attractive force developed in the electro-,magnets R and R2 in accordance with the electrical condition of the line-wire. The proportionate distribution of the tota-l retractile force ofthe spring T between the armature-levers r and r2 will be automatically eft'ected with the utmostnicety by the apparatus described. The retractile force exerted upon the levers r, r', and r2 is so adjusted that the lever r will be attracted to its magnet by a current ot' twelve volts passing over the line L, the lever r by a current of'eighteen volts, and the lever r2 by a current of six volts. With both transmitters at rest (see Fig. l) the current over the line will have an electro-motive force of six volts. This, while not sufficient to overcome the tension ofthe spring t nor to move thelever r', will bejustsuflicient to move the lever ragainstthe contact-point c. Hence the circuitof thebattery e will be closed through both the coils s and s', andthe sounder S will be inactive, as hereinbefore explained. When transmitter K alone is depressed (see Fig. 2) a current of twelve volts is sent to line. This is sufficient to overcome the tension of the spring t and thus close the circuit of the battery e and operate the sounder S. It is not, however, sufficient to move the lever r', and therefore the sounder S remains inactive. When transmitter K' alone is depressed (see Fig. 3) no currentpasses over theline. Hence the lever r remains against the stop a. and the sounder S is inactive. The lever r2 also falls back, breaking the circuit through the coil s of the receiving-instrument S', which is thereupon actuated by the current passing through the coil s. Then both transmitters K and yK are simultaneously depressed (see Fig. 4) a currentof eighteen voltsis sent to line. This overcomes the tension of the spring t and actuates the sounder S. It also causes the levers r' and r2 to be drawn against the stops b and c', respectively. The sounder S' is thereupon actuated by the current passing through the coil s alone.

In Fig. 5 I have shown a modification ofmy invention,in which I replace thetwo independent armatures r and fr2 by two interlocking armature-levers, u' anda?. The armature-lever a is normally held against a fixed stop, b, by means of a tension-rod, t. The working-contact w of the armature-lever u2, instead of heing stationary, is mounted upon the extremity of the pivoted armature-lever u', and a fixed stop is placed in front of the lever u at such a distance as to permit this lever, which is held against the stop b by the tension-rod t',

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t-o yield slightly under the application of sufficient force, and thus to move toward its magnet until arrested by the said stop. The operation of the local circuit of' a relay constructed in this manner is similar to that hereinbefore described in connection 'with Figs. l, 2, 3, and 4, a differential receiving-instrument being included in the circuit of the local battery in the same manner as in the former case. When a current of six volts is passing over the line the armature n? will be attracted toward its magnet, but the force exerted thereby will not be sufficient to overcome the tension of the armature-levend. Thusthecircuitwillbeclosed through each coil of the receiving-instrnment S and no effect produced thereon. A current of twelve volts, though sufficient to actuate the relay R, will not be sufficient to attract thel armature u. A current of eighteen volts,

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however, will attract both armatures u and u2, thus completing a circuit through one coil, s, only ofthe receiving-instrument S. When no current is upon the line, as is the case when the transmittirig-instrument K alone is depressed, neither armature will be attracted, and bath will rest against their back contacts, thus closing the local circuit through the coil s only ofthe receiving-instrulnent S. I prefer to use the allusting device described in connection with Figs. 1,2, 3, and 4 for regulating theten sion upon the armattire-levers u and u2, though it is evident that the usual .tension-spring may be appliedv to each.

I do not herein specifically claim the peculiar arrangement ot' the transmitting device described in the specification and shown in the drawings, as it forms the subjectniatter of a claim in another pending application.

I claim as my inventionl. The combination` substantially as hereinbefore set forth, of two independent electrolnagnets included in the same circ'uit,t\vo armatures and armature levers actuated by the respective. electro-magnets, an equalizing-bar having its extremities attached one to each of' said armature-levers, and an adjustable retractor acting upon said equalizing-bar.

2. The combination, substantially as herein before set forth, ot' two independent electromagnets included in the same circuit, two armatures and armaturelevers actuated by the respective electro-magnets, an equalizing-bar having its extremities attached one t0 each of said armaturelevers, an adjustable retractor acting upon said equalizng-bar, a receivinginstrument actuated by a differential magnet, a local battery, two branch circuits from said battery, each including one coil of said differential magnet, and means, substantially such as described, for closing a circuit through one or through both ot' said branches, according to the position of said armatures.

3. The combination, substantially as hereinbefore set forth, of two independent electro` magnets, each provided with an armature and arm attire-lever, one of said levers constituting a yielding contact-stop for the other, an equalizing-bar having its ends connected one with each of said levers, and an adjustable retractor acting upon said equaliZing-bar.

4. Ilie combination, substantially as hereinbetore set forth, of two electro-magnets, two armatures mounted upon pivoted levers, an equalizing-bar having its respective ends mechanically connected with said levers, al retractor attached to said equalizing-bar, a device forregulating the tension ofsaid retractor, and means, substantially as described, for varying the point of attachment ofthe retractor to the equalizing-bar.

In testimony whereof I have hereunto subscribed my name this 21st day of November, A. l). 1881.

STEPHEN DUDLEY FIELD.

Witnesses:

CHARLES A. TERRY, M. C. EARL. 

